Surfboards are commonly equipped with one or more short, deep, dagger-shaped fins extending downwardly at or near the rear of the board. Such a fin acts as a fixed rudder that depends on the surfer shifting body weight via the legs and their location on the board, for maneuvering and turning. The hydrodynamics involved are extremely complex and ever-changing to the extent that quantitative analysis is practically impossible, therefore the general configuration of present day surfboards is the result of a highly empirical evolution in a quest for perfection that continues on into the future. The arbitrary fixed location of the fin(s) so far to the rear leaves the main portion of the surfboard's smooth bottom subject to side-slip due to the lack of lateral resistance forward of the fin. This can detract from ultimate performance, e.g. slow down the response time on turns due to side-slip in the water, i.e. insufficient "bite".
Amongst known approaches to improve over the simple finned surfboard configuration, there have been attempts to provide additional lateral resistance in the stern region of a surfboard forward of the fin(s) by configuring the bottom of the surfboard with longitudinal channels as an integral part of the surfboard in a manner sometimes found in sailboat and powerboat hulls; however such structure has not become popular in surfboards due to the added manufacturing cost and complexity along with reliability problems since the channel regions proved less robust than a continuously smooth bottom surface, frequently cracking and causing damage to the surfboard. Consequently the great majority of surfboards in general use are configured with a smooth bottom surface and one or more fins located far aft.
In an alternative approach, a group of strips or ridges for enhancing lateral resistance can be individually attached onto an existing surfboard as a retrofit. Depending on the rigidity of the material in the strips and the narrowness of the area available for adhesive attachment, the adhesive layer will generally be subjected to such extremely high stress concentrations that both the adhesive material itself and the craftsmanship of application would be unusually critical and demanding, such that in practice there could be a high risk of unreliability and failure, especially when each strip must be separately attached to the surfboard by the user. Many users may lack the necessary expertise and skills required to apply the critical adhesive properly to each of the strips, and to perform the numerous difficult measurements required on the surfboard in order to get all of the strips accurately located and parallel to each other.